The evening would

[Bassim]

This sentence popped up in my mind. I am not sure if it sounds natural. Would you please correct my grammar and punctuation?

The evening would have been beautiful, if worry had not crept into Peter's mind.

 

[GoesStation]

That looks fine. A slightly more elegant (and old-fashioned) variant: The evening would have been beautiful, had worry not crept into Peter's mind.